Nonlinear integrated steering and control of flight vehicles

Abstract

In this paper, we present an approach to integrated steering and control design for flight vehicles. In this approach, input-output linearization is applied to derive the integrated controller, which performs the function of both autopilot controller and steering law. The nonlinear six degree-of-freedom dynamics together with aerodynamics model of vehicle is considered. Simulation shows that the design has excellent performance and is robust against unmodelled actuator dynamics and uncertainties. Nomenclature b = wing span c = wing chord 8 a = aileron deflection 8 e = elevator deflection 8 r = rudder deflection m = vehicle mass p = body-axis roll rate q = body-axis pitch rate r = body-axis yaw rate; norm of r r = \x y z J vehicle position vector in inertial coordinate C ; = aerodyn. moment coeff. about body x axis C m = aerodyn. moment coeff. about body y axis C n = aerodyn. moment coeff. about body z axis C x = aerodynamic force coeff. in body x axis C y = aerodynamic force coeff. in body y axis C z = aerodynamic force coeff. in body z axis F x = aerodynamic force in body x axis F y = aerodynamic force in body y axisF z = aerodynamic force in body z axis I = vehicle's moment of inertia matrix / =Jacobian matrix of aerodyn force coefficients L = aerodynamic roll moment M = aerodynamic pitch moment N = aerodynamic yaw moment Q = dynamic pressure S = reference area T = engine thrust Ty, = Transformation matrix from body frame to inertial frame V = magnitude of velocity CC = angle of attack /? = sideslip angle \j/ = yaw angle 6 = pitch angle (j) = roll angle C = LOS vector <7 z ,C7 y ,ff z = components of LOS vector in inertial coordinate p =air density Q = skew-symmetric matrix of body rate vector A = Transpose of matrix/vector A